Management of patients with chronic disease consumes a significant proportion of the total health care expenditure in the United States. Many of these diseases are widely prevalent and have significant annual incidences as well. Heart Failure prevalence alone is estimated at over 5.5 million patients in 2000 with incidence rates of over half a million additional patients annually, resulting in a total health care burden in excess of $20 billion. Heart Failure, like many other chronic diseases such as Asthma, Chronic Obstructive Pulmonary Disease (“COPD”), Chronic Pain, and Epilepsy is event driven, where acute de-compensations result in hospitalization. In addition to causing considerable physical and emotional trauma to the patient and family, event driven hospitalizations consume a majority of the total health care expenditure allocated to the treatment of heart failure.
An interesting fact about the treatment of acute de-compensation is that hospitalization and treatment occurs after the event (de-compensation) has happened. However, most Heart Failure patients exhibit prior non-traumatic symptoms, such as steady weight gain, in the weeks or days prior to the de-compensation. If the attending physician is made aware of these symptoms, it is possible to intervene before the event, at substantially less cost to the patient and the health care system. Intervention is usually in the form of a re-titration of the patient's drug cocktail, reinforcement of the patient's compliance with the prescribed drug regimen, or acute changes to the patient's diet and exercise regimens. Such intervention is usually effective in preventing the de-compensation episode and thus avoiding hospitalization.
In order to provide early detection of symptoms that may signal an increased likelihood of a traumatic medical event, patients may receive implantable medical devices (“IMDs”) that have the ability to measure various body characteristics. For instance, IMDs are currently available that provide direct measurement of electrical cardiac activity, physical motion, temperature, and other clinical parameters. The data collected by these devices is typically retrieved from the device through interrogation.
Some IMDs communicate with a repeater located in the patient's home via a short range wireless communications link. The repeater interrogates the IMD and retrieves the clinical data stored within the IMD. The repeater then establishes a connection with a host computer or patient management system and transmits the clinical data.
While the use of a repeater is convenient for a patient while located near the repeater, no data can be transmitted from the IMD to the repeater if the IMD is out of range. Therefore, if the patient is away from home, no data can be communicated to the host computer system via the repeater. This can be extremely inconvenient, and even dangerous, for the patient if a medically significant event occurs while the IMD is out of range of the repeater.
Therefore, in light of the above, there is a need for a method and apparatus for enabling data communication between an IMD and a host computer that enables communication between the IMD and the host computer in a manner that does not require proximity to a fixed repeater device. There is a further need for a method and apparatus for enabling data communication between an IMD and a host computer that utilizes a portable communications device for directly communicating with the host computer.